Field of the Invention
The present invention concerns an external fixation or attachment device intended for use in orthopedic applications, and concerns, more particularly, the said device adapted for use in the method known as the ILIZAROV method.
According to this method, which is widely known, to a bone and/or bone fragment, there is associated a pair of needles or pins presenting a small-sized diameter that intersect substantially at right angles in each bone structure, respectively. Once the ends of the needles have been attached to external supports corresponding to the members to be treated, the said needles are placed under tension and the supports to which the needles are attached are interconnected together by cross-pieces having an adjustable length that comprise means for compressing or extending the whole of the said system and thus applying dynamic action(s) to the said bones or bone fragments. These braces are fixed in predetermined positions through the arrangement of holes or perforations provided at regular distances from one another upon the above-mentioned supports.
External attachment devices intended to be used in applying the ILIZAROV method are already known, i.e. devices or apparatus used for the treatment through compression-extension of fractures, for the treatment of persistently defective calluses of the long bones, or furthermore for the treatment of elongations to be operated on without bleeding, etc.
These known apparatus comprise flat section metal rings or half-rings, comprising prepositioned holes for the fixation of the cross-pieces and adapted to be interconnected to one another by solid metal rods provided with screws, nuts and lock-nuts. However, this assembly is heavy and difficult to handle due to its larger number of constitutive elements so that the apparatus is relatively unsuitable for utilization within a modern medical environment.
Furthermore, known apparatuses also present inherent drawbacks with respect to the medical-surgical point of view. Indeed, the structure of section rings or half-rings as well as the predetermined position of the perforations present on the rings or half-rings do not allow practitioners to achieve the desired accuracy of positioning, especially upon the angular plan, so that with known apparatus the method called the ILIZAROV method has not been as widely used as might have been evisaged.
In a general manner, one of the aims of the present invention is to provide an external fixation or attachment device intended for use in the orthopedic field, adapted to be used in the ILIZAROV method, which is much simpler to use than the known devices.
A further aim of the invention is to provide such device formed of a reduced number of constitutive parts, which thus facilitates transport and which, due to this fact, can be applied under difficult surgical intervention conditions.
It is yet a further aim of the invention to provide such device which overcomes the drawbacks mentioned herein-above inherent in the known devices, especially with respect to the accurate positioning of its constitutive elements relative to the bone to be treated.
Similarly, another aim of the invention is to provide said device which considerably increases the possibilities of surgical therapy due, in particular, to the adaptability of the apparatus according to the invention, to different types of cases, but also due to the ease in its fitting and removal as well as the possibilities of its adjustment.
An external fixation device for orthopedic use adapted to be used with the so-called ILIZAROV method, comprises at least two rings or hoops for the substantially cross-shaped attachment of pins or needles, with cross-pieces intended to connect the said hoops and comprising means for adjusting their length for putting a bone and/or bone fragment to which they are connected under traction or compression, respectively, means being furthermore provided for the putting under tension of the said pins or needles, are characterized according to the invention in that the hoops are produced from a tube having a circular cross-section.
According to one embodiment of the invention, the said device comprises articulated collars being able to be fixed and rendered locked in any given position of the hoops thereby allowing the fixation of braces.
According to another variant of the invention, certain of the said collars can be fixed and rendered locked in any given position of the hoops comprising means for receiving and locking in position one end of the said pins or needles.
According to another variant of the invention, the other ends of the pins or needles are attached to members immovably associated to the said collars.
Preferably, the said members comprise the said adjustable means for putting under tension the said pins or needles.
According to a further embodiment of the invention, the hoops are formed of two half-hoops connected by assembly means.
Preferably, the assembly means are constituted by notched joint-type articulations.